Magnetically operated switch



P ,1931. 'F. A. BOEDTCHER 1,823,252

MAGNETI CALLY OPERATED SWITCH Filed Nov. 22, 1926 BY A770 EYS.

Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE FRANZ A. BOEDTCHER,0F BERGENFIELD, NEW JERSEY, ASSIGNOR T0 OTIS ELEVATOR COMPANY, OF JERSEYCITY, NEW JERSEY, A CORPORATION OF NEW JERSEY MAGNETICALLY OPERATEDSWITCH Application filed November 22, 1926.

This invention is a magnetically controlled switch particularly adaptedfor use in connection with the signalling circuits of elevators andadapted to be automatically operated by the passage of the magnetcarried by the elevator cage.

The switch of this invention embodies a pivoted arm adapted to bemounted in close proximity to the path of a permanent or electromagnet,so that as the magnet moves along its predetermined path, it willoperate the arm as it passes the same.

In practice, the switch arm to which I have referred is generally in theform of a rocker pivoted intermediate its ends and rocking movement isimparted to this switch arm during the passage of the magnet inproximity thereto. When it is borne in mind that elevator cages travelat relatively high speed, not infrequently up to 700 or 800 feet perminute, it is apparent that the interval, during which the magnet is inproper cooperative relation to the switch arm, is relatively short, andthe arm must be operated during this interval in order to function.

My experience coupled with extensive ex periments has shown that if themagnet is made of sufficient power to operate such a switch arm at highspeeds, there is a marked tendency on the part of the switch arm torebound after operation. This is due to several reasons. For example,the switch arm necessarily embodies more or less inertia, which must beovercome before movement can be imparted thereto. If a magnet ofsufficient power is provided to rapidly overcome this inertia, themovement of the switch arm is very rapid, and if it is brought to asudden stop, rebound is almost sure to occur unless some appropriatemeans is provided to lock the parts against such rebound.

The object of the present invention therefore is to provide a switch ofthe character described which may be efficiently and economicallymanufactured and which may be used with a high degree of efliciency inconjunction with rapidly moving elevators and without fear of faultyoperation due to rebound or otherwise.

Speaking generally, the switch of this in- Serial No. 149,886.

vention embodies a pivoted arm which is preferably mounted to rock upona pivot intermedlate its ends. Either one or both ends of the arm carryone or more movable electrlcal contacts, which are adapted to cooperatewith relatively fixed contacts mounted on a suitable adjacent stationarysupport. These so-called relatively fixed contacts are preferably formedso that they will cooperate with the movable contacts in a yieldablemanner to so cushion the operation of the switch arm as to substantiallylock the arm against rebound.

, For cars moving at relatively high speeds,

this cooperative relation between the fixed and movable contacts willserve to eliminate rebound, but in the case of cars movng at very rapidspeeds, a further expedient is preferably associated with the switch armand consists in positioning a link or links beyond the free end or endsof the switch arm and pivotally associating said links with the arm andwith a suitable firm support. The purpose of the links to which I havereferred is to extend the length of time during which the switch arm isresponsive to the pull of the magnet and also to so constitute thestructure that the magnetic force exerted on said arm will be graduallydecreased instead of suddenly discontinued.

In practice, the links may be used exclusively of the spring contactarrangement referred to or vice versa, but the best results are obtainedwhen both of these expedients are employed in the construction of theswitch. A switch thus constructed will not rebound irrespective of themagnetic force applied thereto or irrespecth'e of the speed at which theassociated elevator is operating.

Features of the invention, other than those adverted to, will beapparent from the hereinafter detailed description and claims, when readin conjunction with the accompanying drawings.

The accompanying drawings illustrate one practical embodiment of theinvention, but the construction therein shown is to be under stood asillustrative, only, and not as defining the limits of the invention.

Figure 1 is a front view of a switch embodying the present invention.

Figure 2 is a side elevation of the switch with one fixed contactremoved and the pivotal connection of the upper link shown in section inthe interest of clearness.

Figure 3 is a fragmental section on the line 3 of Fig. 1.

Figure 4 is a. fragmental section on the line H of Figure 1.

Figure 5 is a central longitudinal section through the switch arm atthat point in its length which carries the movable contact, this viewillustrating details of said contact; and,

Figure 6 is a section on the line 66 of Figure 1.

Referring to the drawings, 1 designates a suitable supporting plate.Mounted about midway of the length of the plate is a bracket 2 whichcarries laterally extending pin 3.

Thispin passes through an arm l, and a cotter pin 5is provided topreclude disengagement of the arm from the pin 3.

The arm at constitutes the switch arm of this invention and is adaptedto be rocked on the axis of the pin 3 during the passage of anelectromagnet M in proximity to and. longitudinally of the rocker 4:.

It will be noted that the rocker 4 is bent at its center, so that, whenin either of its extreme positions, one end portion of the rocker willbe substantially parallelwith the path of travel of the magnet. Theadvantage of this arrangement is that it permits the magnet to be setcloser to the rocker than if the rocker were made straight. The extentof pivotal movement to which the rocker is susceptible is limited by astop ring 6 into which extends a cushioning button 7 preferably sheathedwith rubber and carried by one arm of the rocker, as shown in Figures 1and 2.

Associated with either one or both of the opposite ends of the rockerare one or more movable contacts. Any appropriate number of suchcontacts may be employed and they may bemounted on one end of the rockerto the exclusion of the other end thereof if desired. For the purpose ofillustration, however, I have shown one movable contact associated witheach end of the rockor. This contact is in the form of a pin 8 whichextends directly through the rocker and projects beyond the oppositeside there- -of. The detail of the mounting of the pin is shown in Fig.5. Here the rocker 4 is shown as perforated to receive an insulatingbushing 9. Insulating discs 10 are positioned against the opposite facesof the rockor and an eyelet 11 passes through the bushi g and is flangedat its opposite ends over washers'lQ. The eyelet provides a bearingthrough which the contact pin extends and in which said pin' isfloatably supported while the pin is insulated from the rocker 4.

Each pin 8 is adapted to cooperate with contacts positioned adjacent theopposite lateral faces of the rocker, and with which the opposite endsof the pin are adapted to contact to cause the pin to function after themanner of a bridge piece for feeding the current between the contacts.The contacts at one side of the rocker are rigid, and as shown in Figure6, there are two of them 14 carried by a suitable insulating bracket 15secured by means of screws 16 to the supporting plate 1. ,The contact atthe other side of the re -l:er is in the form of a spring plate 17 whichis returned upon itself.

One end of the plate is secured to an upstanding bracket 18 ofconducting material. This bracket is secured by means of screws 19 to aninsulating plate 20 which is, in turn, mounted upon a supportingplate 1. The other end of the spring plate extends into engagement withthe contiguous end of the pin 8, with sutlicient pressure tomaintain'the opposite end of the pin at all times in engagement with oneor the'other of the contacts 14-. The employment of a. spring plate isof importance and the shaping of the plate is material. For example, itwill be noted from Figs. 3 and t that the free end of the plate is widerin a vertical direction as viewed in Figs. 3 and 4, than the end of theplate which is secured to the bracket 18, and that said plate ismoreover longitudinally slotted at 21, so that the relatively long freeend is supported upon relatively narrow resilient arms 22.Thisrelatively long free end to which I have referred is designated 23in Figs. 3 and a and constitutes the working end of the. contact, sinceit is over the face of this portion of the plate that the pin is causedto slide as the rocker is tilted from one position to the other. 7

By the. formation of the plate as specified, it will be apparent thatwhen the rocker is tilted into its terminal positions, the working head23 will be tilted, as shown in Fig. a. That is to say, when the pin isin one terminal position, as shown in full lines, it will tilt the head23, as shown in full lines, whereas when the pin is in the otherterminal position shown in dotted lines, the headv will be 1; similarlytilted as shown in dotted lines. To move from one of these positions tothe other, the pin will be forced to travel along the inclined surfaceof the head 23 until it reaches substantially the center ofthe head andupon further movement of the pin in the same direction, the head willtilt into the op posite position and the pin will readily slide down, asit were, into its other terminal position. the maximum pressure which isbrought to bear by the head upon the pin will be at the center positionfor it is here that the pressure plate is placed under the greatestpressure or retracted to the greatest extent.

With this construction, therefore,-

It therefore follows that by this arrangement, the movement from oneterminal position into the center position must be accomplished by apositive operation of the pin and such movement cannot be inadvertent.It

therefore follows that the structure which I have described willresiliently maintain the rocker in either of its terminal positions andpreclude rebound of the rocker after operation by the magnet M.

In practice, I- preferably use the spring plate which I have described,but it will be apparent to those skilled in the art that thepresentation of inclined surfaces to the movable contact may beaccomplished by other than the specific means described, and the presentinvention is therefore not limited to this illustrative form of theinvention.

It will ofcourse be understood that in practically carrying out theinvention, as thus far described, the circuits to be controlled by theswitch are connected to the contacts 14 and 17 by associating suitablebinding posts with these contacts. These circuits may form part ofsignal setting or resetting circuits, or may, in practice, constituteany other circuits, which it is desired to control by a switch of thecharacter herein described.

To the opposite ends of the rocker 4 are pivoted lin is 24, the distantends of which are supported on suitable brackets 25 through pivotalconnections 26, shown in Figure 2 as capable of permitting longitudinalmovement of the links 24. The opposite ends of the rocker are shown asbifurcated to provide a convenient pivoted connection for the links inquestion, but any other suitable construction would serve the purpose.

In practice, the rocker 1, as well as the links 24 are of metal capableof being attracted by a permanent or electromagnet, and these parts areadapted, in the operation of the switch of this invention, to functionas the armature or armatures of the electromagnet M associatedtherewith. Thus, when the ma net is at any point between the pivot 3 anone of the pivots 26, it will attractthe intervening portion of itsarmature to move the rocker into a corresponding position. If, however,the magnet is moved to the opposite side of the pivot, the other portionof this has moved to a position above the pivot 3 and into substantiallythis position shown in dotted lines. It will then proceed to retractthat portion of the armature above the pivot 3 and will move-thearmature into a. reversed position. The exact point in the travel of themagnet M where this reversal will take place will depend largely uponthe power of the magnet and the speed at which it is moving. If it ismoving at a very high speed, it may pass a considerable distance alongthe upper arm of the rocker before the inertia of the rocker is overcomesufliciently to bring about ashifting thereof. However, the rockercannot rebound even though the resilient plates 17 are insufiicient toovercome this tendency, because the magnet will continue after it leavesthe upper end of the rocker to exert a pull upon the upper link 24 andthis pull will become of less and less force in the holding of therocker against rebound as the magnet nears the upper pivot 26. \Vhen itreaches the pivot, the elfective pull on the link will cease, but bythis time the period of rebounding-tendency has passed.

It therefore appears that the present invention embodies two safeguardsagainst rebounding. Operating oonjointly, the links 2 f and the springplates 17 will positively preclude rebound under the most tryingconditions in the operation of high speed elevators. If the switch is tocooperate with elevators adapted to run at lower speeds, either of theexpedients to which I have referred may be used to the exclusion of theother, but if either is to be omitted, I prefer to omit the links 24 andretain the spring plates 27 since they function with high e'liiciencyand preclude inadvertent shifting of the rocker in directions adverse tothe operations of the magnet and frictiona-lly and resiliently hold theparts in the positions to which they have been set by the magnet.

I do not wish to be understood, however, as minimizing the importance ofthe employment of the links 24. The use of these links of which theremay be more than two, without departing from the invention, enables metoextend the length of the magn-et armature without increasing the distance between the magnet and its armature. That is to say, if the rockerarms were made to extend to the distant ends of the links and form arigid construction, the magnet would have to be placed a relativelygreat distance away from its armature and a magnet of many times thestrength possible to use under the construction de scribed would have tobe employed, and even then the operation would not be dependable.

The employment of a yieldable extension of the armature is thereforehighly important from a practical standpoint.

The use of the spring plate which causes the end of the pin to travelover the inclined surface of the head 23 has an advantage other thanthat hereinbefore referred to, namely, that inherent in the rollingoperation of the pin. In practice, it is found that when the pintraverses the inclined surface of the head 1B0 pin self cleaned. Thisobviates the necessity of frequent inspection and manual cleaning. Theforegomg detailed description sets forth the invention in its preferredpractical form. I am aware, however, that the shape of the several partswhich I have described,

as well as details of construction may be said member to an operatedposition as it comes opposite thereto, and means for precluding reboundof said member from said operated position as the magnet passes beyondsaid member.

2. In an assembly of the character described, a magnetically operableswitch comprising a movable current switching member, a magnet mountedto travel past the current switching member and in proximity thereto,said magnet causing movement of said member to an operated position asit comes opposite thereto, and means operable independently of magneticforce from the magnet, to preclude rebound of said member from saidoperated position as the magnet passes beyond said member.

3. In an assembly of the character described, an electromagnet mountedto travel along a predetermined path, a movable current switching memberpositioned in proximity to said path and adapted to serve as thearmature of said magnet, said magnet attracting said member to anoperated position as it comes opposite thereto during its travel, andmeans for maintaining the current switching member in the position towhich switching element positioned adjacent said the magnet, after themagnet is passed beyond said member.

5. In an assembly of the character described, a magnet mounted to travelalong apredetermined path, a current switching member operable by saidmagnet while the magnet is passing said member, and means operable bythe magnet after it has passed said member to maintain the member in theposition in which the magnet has operated it.

6. In an assembly of the character described, a magnet mounted to travelalong a predetermined path, a rocker mounted to pivotally move on anaxis extending transversely of the path of travel of the magnet, acurrent switching device mounted on said rocker and movable thereby intoand out of cooperation with relatively fixed contacts, and extendingmembers pivotally associated with the rocker and extending beyond theends thereof to provide prolonged cooperation between the rocker and themagnet.

7. In an assembly of the character described, a magnet mounted to travelalong a predetermined path, a current switching member embodying arocker positioned in proximity to the path 'of travel of the magnet andfunctioning as the armature of the magnet, and members pivoted to andextending beyond the ends of the rocker and adapted to also function asarmatures for the magnet, whereby the cooperative relation between themagnet and rocker-is prolonged.

8. In a magnetically operable switch, a member mounted to rock, acontact carried by said member and movable thereby between two welldefined termini, a relatively fixed resilient element hearing at alltimes against the contact of the pivoted member and presenting to saidpivoted member an inclined surface when said contact is at either of itstermini.

9. In a magnetically operable switch, a pivoted member mounted to rock,a movable contact carried by the pivoted member, fixed contacts adaptedto engage with and be traversed by said movable contact as the pivotedmember is moved from one to the other of its termini, and resilientpressure means bearing against a movable contact to force it in thedirection of the fixed contacts, said resilient pressure means embodyingan operating head tiltable. in a direction of travel of the movablecontact and resiliently impelled into such tilted position to present aninclined path to the contact when the latter is in either of itsterminal positions. 7

10. In a magnetic switch, a. pivoted member constituting an armature andcarrying thereon at least one contact, a plurality of relatively fixedcontacts with which the movable contact is adapted to cooperate, and aspring plate bearing against the movable contact at all times to forceit into cooperative relation with the fixed contacts, the resiliency ofsaid plate serving to present an inclined surface to the movable contactwhen said contact is at either of the termini of its travel.

11. In a magnetic switch, a pivoted member constituting an armature andcarrying thereon at least one contact, a plurality of relatively fixedcontacts with which the movable contact is adapted to cooperate, apressure head bearing against the movable con- U tact at all times toforce it into cooperative relation with the fixed contacts, and meansfor supporting said pressure head resiliently to cause it to present aninclined surface to the movable contact when said contact is at eitherof the termini of its travel.

12. In a magnetically operable switch, a movable switch arm, a contactcarried by said arm, and a relatively fixed contact with which themovable contact is adapted to cooperate, said contacts being formed topresent an inclined surface against themovement of one contact away fromthe other.

13. In a magnetically operable switch, a switch arm carrying a movablecontact, a relatively fixed contact mounted to yieldably cooperate withthe movable contact, said fixed contact being formed to present to themovable contact an inclined surface to retain the switch arm againstinadvertent movement.

14. In a magnetic switch, a pivoted member constituting an armature, acurrent bridge piece carried by said member extending parallel to theaxis of pivotal movement of the member and mounted for longitudinalmovement with the opposite ends of the bridge piece exposed, a pluralityof fixed contacts spaced apart and between which the bridge piece isadapted to be moved through movement of said member, at least one ofsaid relatively fixed contacts being resilient whereby the brldge pieceis caused to engage both contacts simultaneously and constitute acurrent bridge therebetween.

15. In an assembly of the character described, a magnetically operableswitch comprising a movable current switching member, a. magnet mountedto travel apass the current switching member and in proximity theretofor the purpose of operating said member,

and magnetically operable means for preeluding rebound of said memberwhen it is operated by the magnet.

In testimony whereof I have signed the foregoing specification.

FRANZ A. BOEDTCHER,

